Haptoglobin is an acute phase protein which is released due to an inflamation or lesion.  It immediately binds free hemoglobin.  It can be used as a marker both for inflamation and for occult blood.  The molecule consists of 774 aminoacids and belongs to the alpha-2-globulins. Haptoglobin is the most sensitive marker to detect a hemolyse in serum. Due to its high stability in stool, it is a promising indicator.